The management of lower pole renal stones (LPS) is often difficult. Extracorporeal shock wave lithotripsy (ESWL), flexible ureterorenoscopy (fURS) and percutaneous nephrolithotomy (PCNL) are all potential options with potential benefits and disadvantages. In order to assess the success of fURS in managing these stones a prospective study looked at patients with LPS treated with fURS over a six-year period. The data from three surgeons were obtained and in total 242 procedures were performed on 198 patients. The indications for fURS for LPS were: patient choice for symptomatic stones, failed ESWL and patients unfit for PCNL. Patients with stones <5mm were managed conservatively. A semi-rigid ureteroscope was used initially prior to fURS to dilate the ureter and a ureteral access sheath was used to enable easier removal of stone fragments in certain cases. Patients were described as stone free if there were either no stones present or fragments were <3mm as assessed by KUB or ultrasound postoperatively. The mean calculi size was 11mm (range 4-27mm), with 37 patients having more than one stone at the LP (range 2-5). 86.4% (171) patients had a stent post-procedure and 40 patients had a re-operation. Stone-free rates after one procedure were 89% for calculi measuring 4-10mm (n=107), 80% for stones 11-20mm (n+76) and 41% for stones >20mm. This improved to a stone-free rate of 79% for stones >20mm after two procedures. Overall stone-free rates were 83%, 91% and 95% after one, two and three procedures, respectively. According to the study’s definition 11 patients were not cleared of their stone burden. Two of these patients subsequently underwent a successful PCNL whilst the remaining nine are under a watchful wait policy. A 2.5% complication rate was reported, these being: two admissions with urosepsis, two ureteric perforations, one renal pelvis perforation and one retained guidewire. Available evidence already suggests that ESWL has poor clearance rates for LPS, especially if the stone size is >10mm. PCNL has therefore been recommended for these patients. This study provides evidence for what a lot of urologists already discuss with their patients i.e. that fURS is a good minimally invasive alternative to PCNL for LPS, especially if <20mm. The authors mention a few limitations to the study which include the varied forms of imaging used to assess stone-free rate post-procedure and the variation in technique used between the three surgeons (one always uses an access sheath, the others don’t). Also despite 171 stents being inserted no stent complications are mentioned which certainly in my practice is the main thing we get contacted about. They also mention that stones <5mm are managed conservatively but report stone free rates for stones 4-10mm. I’m not sure why this discrepancy occurs. I think this is a good study supporting the practice of a large number of endourologists. 

Efficacy of flexible ureteroscopy and laser lithotripsy for lower pole renal calculi.
Sahai A, Khan F, Anjum F, et al.
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Ann Crump

Central Manchester Foundation NHS Trust

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